<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<script>
var x= 10, y=20;
function func(){
	return x+y;
}
</script>
<input type="button" value="덧셈" onclick="alert(func())">
<!-- 버튼을 클릭하면 덧셈 결과가 출력되도록 하시오. 출력함수는 alert()임 -->
</body>
</html>